Proteases that have been hitherto reported are classified into serine/threonine-, metallo-, cysteine- and aspartic-proteases and other classes of proteases comprising protein families characterized as having common protein motif structures. However, proteases that do not possess these structures but have regulating action on the activity of other proteases, cell invasiveness, and smooth muscle contraction and relaxation, as well as proteolytic activity, have not yet been reported.
The inventors of the present invention extracted, purified and isolated an oxytocin receptor active substance from human placental tissue, determined the partial amino acid sequence of the substance (Patent Documents 1 and 2, and Non-Patent Document 1), further determined the structure of the gene encoding the protein (Patent Document 3 and Non-Patent Document 1), and showed the presence of splice variants of the gene in the term human placenta (Non-Patent Document 1). The inventors investigated the physiological action of the subject protein and disclosed that the protein has relaxing activity on uterine smooth muscles (Patent Document 3) and proteolytic activity (Patent Document 4 and Non-Patent Document 1). However, it was not shown whether the subject protein has regulating action on the activity of other proteases, that is, its usefulness in the treatment, prevention and diagnosis of various diseases; regulating activity on cell invasiveness, that is, its usefulness in the treatment of cancer and related diseases; contracting and relaxing activities on uterine smooth muscles or in broad terms, regulating activity on the function of uterine smooth muscles, that is, its usefulness in the treatment, prevention and diagnosis of various perinatal diseases.
Patent Document 1: JP-A No. 2000-095797
Patent Document 2: JP-A No. 2003-226699
Patent Document 3: JP-A No. 2005-210901
Patent Document 4: JP-A No. 2004-344156
Non-Patent Document 1: J. P. Lee Motoyama (Shizuo Motoyama), H. Kim-Motoyama (Kaoru Motoyama), P. Kim, H. Nakagama, K. Miyagawa, K. Suzuki, Identification of dermcidin in human gestational tissue and characterization of its proteolytic activity, Biochem. Biophys. Res. Commun. 357 (2007), pp. 828-833